* MeeGo chief Ari Jaaksi leaves Nokia
* First MeeGo phone due to be unveiled by year-end
* Jaaksi follows exit of smartphones chief Vanjoki
(Adds Nokia comment, background, shares; changes dateline from HELSINKI)
HELSINKI/LONDON, Oct 5 (Reuters) - Ari Jaaksi, the head of Nokia's MeeGo software platform which it is betting on to fight back against Apple Inc, is leaving the company ahead of the first MeeGo phone launch, Nokia said on Tuesday.
Under the new leadership of Stephen Elop, Nokia has promised to unveil the first device using MeeGo by the end of the year. Anssi Vanjoki, who ran Nokia's key smartphones and services business, also resigned following Elop's appointment.
Asked about Jaaksi, a Nokia spokesman said: "He has decided to leave Nokia and will pursue new opportunities elsewhere."
Nokia, once the envy of the industry for its global reach and coveted phones, has fallen behind new market entrants Apple, Google and others in the high end of the market.
It brought in outsider Elop, a Canadian with Silicon Valley experience and the first non-Finn to run the company, in the hope of injecting a fresh perspective.
"Nokia needs to step up on the MeeGo side. MeeGo has grown up from Maemo and there is much more at stake now," said Gartner analyst Carolina Milanesi. "They need someone who understands mobile and PC, who might be closer to Intel and a much better public person."
MeeGo is a merger of Nokia's Maemo software, which Jaaksi helped build up, and chipmaker Intel's Moblin.
Nokia shares rose 2 percent to 7.475 euros by 1415 GMT, outperforming the European technology index, which rose 1.1 percent.
Nokia controls 40 percent of the smartphone market with its older Symbian software but has lost its leading position among the most expensive models to its new rivals. (Reporting by Tarmo Virki and Georgina Prodhan; Editing by Will Waterman and David Holmes)